CN112114278A

CN112114278A - Magnetic field sensor arrangement, magnetic torque sensor arrangement and method for determining stray field immunity of magnetic flux

Info

Publication number: CN112114278A
Application number: CN202010558757.8A
Authority: CN
Inventors: J·毕尔巴鄂德蒙迪扎巴尔
Original assignee: Melexis Electronic Technology Co ltd
Current assignee: Melexis Electronic Technology Co ltd; Melexis Technologies SA
Priority date: 2019-06-21
Filing date: 2020-06-18
Publication date: 2020-12-22
Also published as: US11852555B2; EP3754356A1; EP3754356B1; US20200400516A1

Abstract

A magnetic field sensor arrangement (220) for determining a signal magnetic flux in a substantially stray field immune manner, comprising: a source of a signal magnetic field (S1); a first and a second flux concentrator forming an air gap (203) between outer faces (204, 205) of the flux concentrators; a magnetic flux concentrator is configured for directing the signal magnetic flux in a gap direction (206) to and through the air gap (203); a magnetic field sensor (207) arranged inside the air gap (203) and configured for measuring a first and a second signal (Bx, Bz) in the air gap direction and in a direction perpendicular to the air gap; and for reducing or eliminating magnetic interference fields based on the first and second signals (Bx, Bz). An angle sensor arrangement. A torque sensor. A method for measuring signal magnetic flux, angle, torque in a substantially stray field immune manner.

Description

Magnetic field sensor arrangement, magnetic torque sensor arrangement and method for determining stray field immunity of magnetic flux

Technical Field

The present invention relates generally to the field of magnetic field sensor arrangements, and in particular to a magnetic field sensor arrangement for determining a magnetic flux generated by a magnetic field source while being substantially immune to magnetic interference or stray fields generated by another magnetic field source. The invention also relates to a magnetic torque sensor arrangement immune to magnetic interference or stray fields. Furthermore, the present invention relates to a method of immunizing against stray fields for determining the magnetic flux generated by a magnetic field source while substantially immunizing against magnetic interference or stray fields generated by another magnetic field source.

Background

Magnetic sensor systems, in particular linear position sensor systems and angular/rotational position sensor systems, are known in the art. They offer the advantage that the linear or angular position can be measured without physical contact by means of a magnetic field sensor arrangement, thereby avoiding problems of mechanical wear, scratching, rubbing, etc.

For example, measurement of the angle of rotation is required in various applications, such as position and/or torque detection of manual electrical switches or motor shafts, valves, etc.

It is known, for example from DE10222118a1, that a magnetic sensor system for determining the torque exerted on a steering column of a vehicle is known, comprising a magnetic field sensor arrangement by means of which an angular displacement between an input shaft portion and an output shaft portion of the steering column is determined using a magnetic field. The magnetic field to be measured and representing the angular displacement between the two shaft portions is generated by a magnetic field source, for example a (multi-pole) permanent ring magnet, which is connected (directly or indirectly) in a rotationally fixed manner to one of the input shaft and the output shaft. The magnetic flux of the generated magnetic field is received and guided by two appropriately shaped flux concentrators, one of which is fixed in a non-rotating manner to the input shaft and the other of which is fixed in a non-rotating manner to the output shaft. The magnetic field sensor measures magnetic flux in an air gap formed between the two flux concentrators, wherein the magnetic flux in the air gap varies as a function of the angular displacement between the input shaft portion and the output shaft portion.

EP3505894 describes a torque sensor comprising a multi-pole ring magnet and two yokes connected to an input shaft and an output shaft, respectively. The yokes have projections forming air gaps. A sensor device is placed in the air gap for measuring the change in magnetic flux density indicative of the angular displacement between the two yokes, which angle itself is indicative of the torque applied to the input and output shafts. The torque sensor is designed to reduce or eliminate assembly errors, but is not immune to external interfering fields.

With the increasing compactness of electrical systems, particularly with hybrid-engine automobiles or pure electric trains, such magnetic sensor systems are often additionally exposed to external magnetic fields from nearby current conductors carrying high currents (e.g., in excess of 100A). Such external magnetic fields (also referred to herein as (external) magnetic interference fields or (external) magnetic stray fields) generated by external magnetic field sources (also referred to herein as disturbing magnetic field sources), e.g. passing through the above-mentioned current conductors in the vicinity of the actual magnetic sensor system, may damage the measured values determined by the sensor system, thereby degrading the accuracy of the linear position or the angular/rotational position to be determined.

It is a challenge to create a magnetic sensor system that is substantially immune (i.e., substantially insensitive) to such external magnetic interference fields or external magnetic stray fields.

There is always room for improvement or replacement.

Disclosure of Invention

It is an object of embodiments of the present invention to provide a magnetic field sensor arrangement and a method for determining a magnetic flux (e.g. a magnetic flux generated by a magnetic field source and modulated by a magnetic structure) while being substantially immune to (external) magnetic interference fields, in particular substantially immune to substantially homogeneous magnetic interference fields.

It is an object of embodiments of the present invention to provide an angle sensor arrangement for determining angular displacements in a manner that is substantially immune to (external) magnetic interference fields, in particular to substantially homogeneous magnetic interference fields, and a method.

It is an object of embodiments of the present invention to provide a magnetic torque sensor arrangement, and a method for determining torque in a manner that is substantially immune to (external) magnetic interference fields, in particular to substantially homogeneous magnetic interference fields.

It is an object of embodiments of the present invention to provide a magnetic sensor arrangement and/or an angle sensor arrangement and/or a magnetic torque sensor arrangement adapted to provide highly accurate measurements (e.g. angular displacement, and/or torque measurements) even in the presence of (external) magnetic interference fields, and a method of immunologically determining magnetic flux with the same characteristics for stray fields.

It is an object of embodiments of the present invention to provide a magnetic sensor arrangement and a magnetic torque sensor arrangement having a compact configuration, thus requiring only a small installation space.

It is an object of embodiments of the present invention to provide a magnetic sensor arrangement, a magnetic torque sensor arrangement and a method for stray field immune determination of magnetic flux that only require relatively simple arithmetic (such as e.g. addition, subtraction, multiplication, division, look-up tables, interpolation) that can be performed on a simple microprocessor or microcontroller, but do not include Discrete Fourier Transform (DFT) or Fast Fourier Transform (FFT) that typically requires a Digital Signal Processor (DSP) and typically also requires a considerable memory capacity (e.g. RAM, ROM, flash memory etc.).

It is an object of embodiments of the present invention to provide a torque sensor for measuring the torque applied to an input shaft and an output shaft in a manner that is highly insensitive to uniform disturbance fields.

These and other objects are achieved according to embodiments of the present invention by a magnetic field sensor arrangement for stray field immune determination of magnetic flux, a magnetic torque sensor arrangement for stray field immune determination of torque and a method for stray field immune determination of magnetic flux.

It is noted that the individual features listed in the following description may be combined with one another in any technically meaningful way and represent further embodiments of the invention. The invention has been further characterized and described with particular reference to the accompanying drawings.

Furthermore, it should be noted that the conjunction "and/or" herein used to combine the first and second features should always be interpreted as disclosing a first embodiment of the invention that may include only the first feature, a second embodiment of the invention that may include only the second feature, and a third embodiment of the invention that may include both the first and second features.

According to a first aspect, the present invention provides a magnetic field sensor arrangement for determining a signal magnetic flux generated by a signal magnetic field source in a manner substantially immune to a magnetic interference field; the magnetic field sensor arrangement comprises: the signal magnetic field source; a first and a second magnetic flux concentrator configured and arranged such that an air gap is formed between an outer face of the first magnetic flux concentrator and an outer face of the second magnetic flux concentrator, wherein the first and the second outer faces define a first direction of the air gap by a line of shortest distance between the outer faces; wherein the first and second flux concentrators are configured to direct a signal magnetic flux generated by the signal magnetic field source substantially in a first direction to and through the air gap; a magnetic field sensor comprising a plurality of sensor elements arranged inside the air gap; wherein the magnetic field sensor is configured for measuring a first signal indicative of a magnetic field component oriented in the first direction and for measuring a second signal indicative of a magnetic field component oriented in a second direction substantially perpendicular to the first direction; and wherein the magnetic field sensor is further configured for reducing or substantially eliminating the influence of a magnetic interference field, if present, based on the first signal and the second signal.

The two outer faces are the respective outer faces of the first and second flux concentrators, respectively, with the distance between the two outer faces being the smallest. Or in other words, between the surface area of the first flux concentrator and the surface area of the second flux concentrator, an "air gap" is formed at the location where the distance between the first flux concentrator and the second flux concentrator is minimal (since this is where most of the flux lines will pass). The "gap direction" of the air gap is defined by a line of shortest length (or shortened distance) between the two outer faces, i.e. the outer face of the first flux concentrator and the outer face of the second flux concentrator, forming and delimiting the air gap with respect to at least one spatial direction.

Although the flux concentrators are "intended" to direct only the magnetic flux generated by the signal magnetic source (e.g., a multi-pole ring magnet), in practice, in the presence of an external disturbance field, the first and second flux concentrators will also receive and direct a first portion of the external magnetic disturbance field through the gap in the first direction, which will affect the first signal. The second part of the disturbing field traverses the air gap from a direction different from the direction of the gap (e.g. substantially perpendicular to the direction of the gap), or from a direction of its line of sight-at least in the area of the cross section of the air gap traversed by the second disturbing magnetic flux-which is not blocked by either of the first and second flux concentrators. Thus, although the second part of the disturbing magnetic flux may be slightly influenced by the presence of the first flux concentrator and/or the second flux concentrator near the air gap, it is never received by the first flux concentrator and the second flux concentrator and guided to the air gap in the direction of the gap in the first flux concentrator and the second flux concentrator.

It is important that the magneto-sensitive element of the sensor device is arranged inside the air gap such that it is able to sense the "signal magnetic flux and the first disturbing magnetic flux" in a first sensing direction, and the "second disturbing magnetic flux" in the sensing direction. By "arranged in the air gap" is meant that the sensor device is arranged such that all its magneto-sensitive elements (e.g. hall-plates) are located inside a "virtual channel" in which most of the magnetic flux is transferred from the first to the second flux conductor. The "virtual channel" is located between the first and second outer faces.

Or in other words, the sensor device is adapted to measure a superposition of the desired magnetic flux (e.g. originating from the magnet) and said (undesired) "first part" of the disturbing field in a first direction, and to measure said "second part" of the disturbing field in a second direction. The first portion and the second portion are related to each other, e.g. proportional to each other. The measurement of the second portion may be used to estimate the first portion, which may then be subtracted from the measured signal in order to determine the (desired) signal flux. Depending on the application, the "signal flux" may indicate a linear position or an angular position. Even in the presence of magnetic interference fields, by reducing or substantially eliminating the effects from the self-interference fields, the signal flux or linear or angular position can be more accurately determined.

An important advantage of the magnetic field sensor arrangement according to the invention is that the magnetic field sensor is arranged in the air gap such that it is able to sense in a first sensing direction of the magnetic field sensor both a signal magnetic flux and a first disturbing magnetic flux (or "first portion") which, in their superimposed state, enter and pass through the air gap, substantially in the gap direction, and is able to simultaneously sense in a second sensing direction of the magnetic field sensor a second disturbing magnetic flux (or "second portion") which enters the air gap independently of the signal magnetic flux from a spatial direction different from the gap direction (e.g. substantially perpendicular to the gap direction), because in this way the amount of the external disturbing magnetic flux (i.e. the disturbing magnetic flux which is present at a given time around the actual magnetic field sensor arrangement) can be determined by the magnetic field sensor in its second sensing direction, thus facilitating the determination of the amount of the first disturbing magnetic flux, sensed by the magnetic field sensor in its first sensing direction, which superposes the signal magnetic flux within the first and second flux concentrators. Knowing the actual amount of the first disturbing magnetic flux makes it possible to cancel (or at least substantially suppress) the influence of the external disturbing magnetic field generated by the disturbing magnetic field source from the total magnetic flux (signal magnetic flux and first disturbing magnetic flux) sensed in the first sensing direction, thereby facilitating the determination of the real signal magnetic flux received by and guided within the first and second flux concentrators. As a result, isolation of the amount of interference generated by the interfering magnetic field source is facilitated, such that the magnetic field sensor arrangement according to the present invention is substantially insensitive or immune to external magnetic stray/interfering fields.

Or in other words, by measuring the "second part" of the disturbing field, for example in a direction substantially perpendicular to the gap direction, the amplitude of the "first part" of the disturbing field can be determined or at least estimated. By subtracting the first part of the estimate, the influence from the interference field can be greatly reduced or even completely eliminated. This is especially true for uniform interference fields.

An advantage of the magnetic field sensor arrangement according to the invention is that the determination of the signal magnetic flux is substantially insensitive to external magnetic stray/disturbing fields, resulting in a considerably more accurate measurement and determination result.

Or more specifically for a sensor arrangement for measuring torque, has the advantage that the torque can be determined with a higher accuracy in a manner that is less sensitive (e.g. substantially insensitive) to magnetic interference fields, in particular homogeneous interference fields.

Furthermore, the magnetic field sensor arrangement according to the present invention has the advantage that a relatively simple controller (e.g. a microcontroller) can be used for determining the signal flux and that no powerful processor is required, since the operations required for determining the signal flux may for example be based on basic operations like addition, subtraction, multiplication, division, goniometric functions and/or look-up tables, but do not require for example a Discrete Fourier Transform (DFT). It should be noted that the goniometric function itself may also be performed using a look-up table and optionally interpolation.

A further advantage of the magnetic field sensor arrangement according to the invention is that stray field immunity is achieved by the new arrangement and/or orientation of the first and second flux concentrators and the magnetic field sensor, in particular by orienting the air gap and the gap direction, respectively, in the manner disclosed herein, such that on the one hand a signal magnetic flux (e.g. generated by a multipole magnet) combined with a first disturbing magnetic flux (e.g. a first part of a disturbing field (e.g. a substantially uniform disturbing field)) and on the other hand a separate second disturbing magnetic flux (e.g. a second part of said disturbing field) cross the air gap independently of each other in two different spatial directions, which facilitates a highly compact design requiring only a small installation space. In a preferred embodiment, the sensor device is realized on a single semiconductor substrate arranged in said air gap.

The expression "substantially perpendicular" should be understood to include angular dimensions of 90 ° and minor deviations from 90 ° which are within common tolerances consistent with the manufacture of the magnetic field sensor and are therefore not a result of a targeted action. Such deviations may include an angular range of between approximately 85 ° and 95 °, preferably between 87 ° and 93 °, more preferably between 89 ° and 91 °.

It is an advantage of the invention that the second signal can be used to reduce or substantially eliminate the first part of the external disturbing field based on the first and second magnetic field components measured in said first and second directions.

Without loss of generality and without limitation thereto, disturbing magnetic fields may be generated by current wires. Although, strictly speaking, the magnetic field created by this current does not create a uniform field, in practice, the magnetic interference field may be considered "substantially uniform" at a sufficient distance from the conductor (e.g. at least 10cm or at least 20cm from the current conductor). In other words, in addition to the magnetic flux provided by the magnetic source (e.g. the permanent magnet), the first part of the disturbing field is also received by the first and second flux collectors and guided together with the signal magnetic flux within the first and second flux collectors, thereby blurring the actual signal magnetic flux.

An advantage of the arrangement of the magnetic field sensor with a first sensing direction substantially aligned with the gap direction is that this facilitates (on the one hand) the sensing of the signal magnetic flux superimposed by the first disturbing magnetic flux in the first sensing direction (equal to the gap direction) and (on the other hand) the sensing of the second disturbing magnetic flux in the second sensing direction by the magnetic field sensor independently of each other and provides a measurement signal which is as high as possible. Thus, the measurement accuracy of the magnetic field sensor arrangement according to the present embodiment is further improved.

In an embodiment, the magnetic field sensor is configured to reduce or substantially eliminate the influence of the magnetic interference field, if present, by scaling the second signal with a predefined constant and by subtracting the scaled signal from the first signal.

This function may be implemented in analog circuitry or digital circuitry. The processing circuitry is preferably also embedded in the same magnetic field sensor, preferably on the same semiconductor substrate. Note that the processing circuitry may, but need not, be located inside the air gap. It is sufficient that the magneto-sensitive element is located inside the air gap.

In an embodiment, the magnetic field sensor further comprises a processor unit and a memory unit.

Note that the specific magnetic gain (magnetic amplification) caused by the flux concentrator guiding the first disturbing magnetic flux may be taken into account before subtracting the non-amplified external second disturbing magnetic flux sensed in the second sensing direction. Such an amplification factor between the first interfering magnetic flux and the second interfering magnetic flux may be determined by calibration or parameterization of the magnetic field sensor arrangement and may be stored later (e.g. during production or during a calibration process) in a non-volatile memory of the memory unit. Integrating the processor unit and the memory unit together with the magnetic sensor on a single semiconductor substrate further improves the compact design of the magnetic field sensor arrangement according to the invention.

According to a second aspect, the present invention provides an angle sensor arrangement comprising: the magnetic field sensor arrangement according to the first aspect; a first ring comprising a plurality of claws, the first ring disposed adjacent to the first magnetic flux concentrator; a second ring comprising a plurality of claws, the second ring disposed adjacent to the second magnetic flux concentrator; the first ring and the second ring are movable about an axis of rotation and relative to each other; and wherein the magnetic field sensor is further configured for converting the signal magnetic flux into an angular distance signal indicative of an angular distance between the first ring and the second ring.

It is noted that with regard to the effects and advantages of the features disclosed herein with regard to the angle sensor arrangement, reference is made in its entirety to corresponding similar features of the magnetic field sensor arrangement disclosed herein and to their effects and advantages.

The signal magnetic field source may be a multi-pole ring magnet. The ring magnet may be radially magnetised. The first and second rings may be rotatable relative to each other about an axis of rotation. The first and second rings may have a plurality of protrusions or pads or claws extending in the axial direction. These projections or pads or claws may have a geometry corresponding to that of the multipole ring magnet, in particular in terms of the number of poles and the number of pads, similar or identical to that described in DE10222118a1 or EP3505894a1, for example. As the first ring rotates relative to the second ring, the magnetic flux generated by the signal source is modulated as a function of the angular displacement. The ring magnet may be fixedly (directly or indirectly) connected to one of the rings.

In an embodiment, the magnetic field sensor is configured for measuring a first magnetic field component in a radial direction with respect to the rotation axis; and wherein the magnetic field sensor is configured for measuring a second magnetic field component in an axial direction parallel to the axis of rotation.

In an embodiment, the outer face of the first magnetic flux concentrator is arranged on a portion of the first magnetic flux concentrator, which portion has a protrusion or a curved portion or an L-shaped cross-section in a plane containing the rotational axis and the first direction (or the gap direction).

In a further or another embodiment, the outer face of the second magnetic flux concentrator is arranged on a portion of the second magnetic flux concentrator, the portion having an L-shaped cross-section in a plane containing the axis of rotation and the first direction (or gap direction).

It should be understood that the respective portion of the first and/or second flux concentrator providing the respective outer face delimiting the air gap with respect to the gap direction may also be referred to as a portion of the respective flux concentrator located near or adjacent to the air gap. The relevant cross-section is taken from the intersecting plane in the direction of the gap direction.

In an embodiment, the L-shaped portion of the first and/or second flux concentrator comprises a long leg and a short leg, wherein the long leg is longer than the short leg, and wherein the long leg is oriented substantially perpendicular to the gap direction.

With regard to the meaning of the expression "substantially vertical", reference is made to the explanations set forth above, which explanations are valid throughout the description. Similarly, according to the invention, the relative term "longer" should be interpreted as that the difference in length between the long leg and the short leg must not be within common tolerances consistent with the manufacture of the first and/or second flux concentrator, but is a result of a targeted action. As an example, the long leg may be at least 10% or at least 20% longer than the short leg.

According to the above L-shaped configuration and arrangement, the second disturbing magnetic flux can reach and cross the air gap substantially perpendicular to the gap direction without being received by, in particular guided within, the first and/or the second flux concentrator. The first and/or second flux concentrator, if any, and in particular the L-shaped portion of the first and/or second flux concentrator, influence the second interfering magnetic flux at most in an insignificant manner. Thus, a line of sight in the direction of the second disturbing magnetic flux entering and crossing the air gap is not blocked by the first and/or the second magnetic flux concentrator, thus facilitating the magnetic field sensor to accurately sense/measure/determine the second magnetic disturbing flux present and extending outside the first and the second magnetic flux concentrator.

In an embodiment, the outer face of the first magnetic flux concentrator is arranged on a portion of the first magnetic flux concentrator forming the free end of the first magnetic flux concentrator.

In an embodiment, the outer face of the second magnetic flux concentrator is arranged on a portion of the second magnetic flux concentrator forming a free end of the second magnetic flux concentrator.

In this way, an improved control of the direction in which the magnetic flux (signal magnetic flux and first disturbing magnetic flux) guided by and within the first and/or second flux concentrator is guided into the air gap is made, i.e. preferably oriented substantially in the gap direction. As mentioned above, the gap direction is preferably oriented substantially in a plane perpendicular to the axial direction of the magnetic arrangement. The gap direction may for example be oriented substantially in a radial direction. The axial direction may be parallel to the input and output shafts, if present. Thus, an increased concentration of magnetic flux passing through the air gap between the outer face of the first magnetic flux concentrator and the outer face of the second magnetic flux concentrator is achieved.

In an embodiment, the outer face of the first magnetic flux concentrator is disposed on a portion of the first magnetic flux concentrator that includes the at least one fin-shaped extension member.

In an embodiment, the outer face of the second flux concentrator is arranged on a portion of the second flux concentrator comprising at least one fin-shaped extension member, wherein the at least one fin-shaped extension member extends beyond a width and/or a height of a cross section of the air gap in a direction oriented substantially perpendicular to the first direction, wherein the cross section of the air gap extends substantially perpendicular to the first direction.

An advantage of this embodiment is that the at least one extension member provides an even further improved control of the direction of an external disturbing magnetic flux originating from the disturbing magnetic field source and entering the air gap from the outside, where the external disturbing magnetic flux is sensed by the magnetic field sensor through its second sensing direction. Furthermore, depending on the spatial extent of the fin-shaped extension member, it may provide a certain shielding effect, if so desired, in order to prevent interfering magnetic fluxes other than the first interfering magnetic flux and the second interfering magnetic flux and originating from a spatial direction perpendicular to the direction of the second interfering magnetic flux from being sensed by the magnetic field sensor in the air gap, although the magnetic flux does not substantially impair the signal magnetic flux to be determined by the angle sensor arrangement (e.g. as part of the torque sensor). Thus, the accuracy of determining the signal flux is further improved.

In an embodiment, the magnetic field sensor comprises a semiconductor substrate located substantially inside the air gap and oriented such that the axial direction is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate comprises an Integrated Magnetic Concentrator (IMC) and at least two horizontal hall elements arranged at the periphery of the IMC.

In an embodiment, the magnetic field sensor comprises a semiconductor substrate located substantially inside the air gap and oriented such that the first direction is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate comprises an Integrated Magnetic Concentrator (IMC) and at least two horizontal hall elements arranged at the periphery of the IMC.

In an embodiment (e.g., as shown in fig. 4 (a)), the magnetic field sensor comprises a semiconductor substrate located substantially inside the air gap and oriented such that the semiconductor substrate is perpendicular to the axial direction, and wherein the semiconductor substrate comprises a horizontal hall element and a vertical hall element.

In an embodiment (e.g., as shown in fig. 4 (b)), the magnetic field sensor comprises a semiconductor substrate located substantially inside the air gap and oriented such that the semiconductor substrate is parallel to the axial direction and to the first direction, and wherein the semiconductor substrate comprises a first vertical hall element sensitive in the first direction and a second vertical hall element sensitive in the axial direction.

In an embodiment (e.g., as shown in fig. 3 (c)), the magnetic field sensor comprises a semiconductor substrate located substantially inside the air gap and oriented such that the semiconductor substrate is perpendicular to the radial direction, and wherein the semiconductor substrate comprises a horizontal hall element and a vertical hall element.

In other words, the sensor device may comprise, for example, an Integrated Magnetic Concentrator (IMC) and two horizontal hall elements arranged at the periphery of said IMC for determining the magnetic field component oriented perpendicular to the semiconductor substrate (e.g. by adding the signals from the two hall elements) and for determining the magnetic field component parallel to the semiconductor substrate (e.g. by subtracting the signals from the two hall elements), but the invention is not limited thereto, and sensor devices with horizontal hall elements and vertical hall elements may also be used.

An advantage of using a magnetic sensor device with only a small number of sensing elements (e.g. only two sensing elements) is that this allows for a highly compact design of the magnetic field sensor arrangement according to the invention.

Furthermore, in some embodiments, an internal flux concentrator (also referred to as IMC) associated with the sensor advantageously amplifies a second interfering magnetic flux (e.g., passively amplifies a magnetic component parallel to the semiconductor plane) to be sensed in a second sensing direction, the second interfering magnetic flux entering the air gap without receiving amplification of the first and second flux concentrators (as opposed to the signal magnetic flux and the first interfering magnetic flux, which are both directed by the first and second flux concentrators in the first sensing direction).

The magnetic sensor device may comprise, for example, two sensing elements for measuring a magnetic field component in a first direction and two other sensing elements for measuring a magnetic field component in a second direction. In a particular embodiment, the sensor device includes four horizontal hall elements (e.g., first, second, third, fourth horizontal hall elements) arranged at the periphery of the circular IMC at 90 ° intervals. The signals from the first and third elements, which are 180 ° apart, may be summed to measure the first magnetic field component. The signals from the second and fourth elements, which are 180 ° apart, may be subtracted to measure the second magnetic field component. An advantage of using four sensors (rather than just two) is that they allow two pairs of horizontal hall elements to be tuned or matched independently to improve accuracy.

Preferably, the magnetic field sensor comprising the sensing element or elements may be arranged within a single chip package (e.g. a plastic molded package), although this is not absolutely required.

According to a third aspect, the present invention provides a magnetic torque sensor arrangement for stray field immune determination of a torque exerted on a torque rod, comprising: the angle sensor arrangement according to the second aspect; said torque rod having a first axial end connected (directly or indirectly) to a first ring and a second axial end connected (directly or indirectly) to a second ring such that when a torque is applied to the torque rod, the torque rod elastically deforms, thereby causing an angular displacement of the first and second rings as a function of the applied torque; and wherein the magnetic field sensor is further configured for converting the signal magnetic flux or the angular displacement into a torque value.

This conversion may be implemented in a manner known per se, for example using a mathematical expression, or a look-up table with optional interpolation.

It is noted that with regard to the effects and advantages of the features disclosed herein with regard to the magnetic torque sensor arrangement, reference is made in its entirety to corresponding similar features of the magnetic field sensor arrangement and/or the angle sensor arrangement disclosed herein, as well as to effects and advantages thereof. Thus, unless explicitly stated otherwise, features of the magnetic field sensor arrangement and/or features of the angle sensor arrangement disclosed herein should also be considered as applicable to the defined features of the magnetic torque sensor arrangement according to the present invention. Likewise, unless explicitly stated otherwise, the features of the magnetic torque sensor arrangement disclosed herein should also be regarded as applicable to the defined features of the magnetic field sensor arrangement or angle sensor arrangement according to the invention. Therefore, for the purpose of simplicity and clarity of this description and to enhance the comprehension of the principles of the present invention, repetition of the explanation of such similar features, effects and advantages thereof is hereinafter largely omitted.

The present invention also provides a method for stray field-immunologically determining a signal magnetic flux generated by a signal magnetic field source in a manner that is highly immune to magnetic interference fields (e.g., uniform interference fields), the method comprising the steps of: a) providing a magnetic structure comprising a magnetic source and two magnetic concentrators configured for guiding a magnetic flux generated by said source and forming an air gap oriented in a radial direction with respect to the magnetic structure; b) measuring a first magnetic field component signal oriented in a radial direction inside the air gap, the first magnetic field component signal being indicative of a combination of a signal generated by a magnetic source and a first portion of a disturbing field oriented in an axial direction with respect to the magnetic structure; c) measuring a second magnetic field component signal oriented in an axial direction of the magnetic structure inside the air gap, the second magnetic field component signal being indicative of a second portion of the disturbing field oriented in the axial direction with respect to the magnetic structure; d) reducing or eliminating the first interference portion by scaling the second signal by a predefined constant and by subtracting the scaled signal from the first signal; e) the corrected first signal is optionally converted into an angular distance value and/or a torque value, for example using a mathematical expression or a look-up table.

One method comprising steps a) to e) is a method of measuring angular distances and/or a method of measuring torque values in a manner that is highly immune to magnetic interference fields.

The present invention also provides a method for stray field-immunologically determining a signal magnetic flux generated by a signal magnetic field source in a manner that is highly immune to magnetic interference fields (in particular, uniform interference fields) using a magnetic arrangement according to the first aspect, the method comprising the steps of: a) receiving, by the first and second flux concentrators, the signal magnetic flux and the first portion of the interference field and directing the signal magnetic flux and the first portion of the interference field into and through the air gap within the first and second flux concentrators; b) measuring a first magnetic signal oriented in a first direction, the first magnetic signal indicative of the combination of the first portion of signal magnetic flux and interference magnetic flux; c) measuring a second magnetic signal oriented in a second direction perpendicular to the first direction, the second magnetic signal indicative of the second portion of the interfering magnetic flux; d) the signal flux is determined based on the first magnetic signal and the second magnetic signal.

In an embodiment, step d) comprises: the second magnetic signal is scaled by a predefined constant and subtracted from the first magnetic signal, thereby reducing or substantially eliminating the effect of the first interfering magnetic flux.

The present invention also provides a method for stray field-immunologically determining the signal flux generated by a signal magnetic field source in a manner that is highly immune to a uniform interfering field, the method comprising the steps of: a) receiving, by the first and second flux concentrators, a first portion of the signal magnetic flux and the interference field and directing the signal magnetic flux and the first portion of the interference field substantially in a gap direction into and through an air gap formed between an outer face of the first flux concentrator and an outer face of the second flux concentrator, wherein the two outer faces are respective outer faces of the first and second flux concentrators, respectively, having a minimum distance therebetween, and the gap direction of the air gap is defined by a line of shortest length therebetween; b) determining a first portion of the signal magnetic flux and the disturbing magnetic flux by a first sensing direction thereof by means of a magnetic field sensor arranged in the air gap and configured for being sensitive to a magnetic field at least in the first sensing direction and in a second sensing direction, wherein the first sensing direction and the second sensing direction are substantially perpendicular to each other; c) determining, by means of the magnetic field sensor, a second portion of the disturbing magnetic flux by a second sensing direction thereof, which second portion crosses the air gap without being received by and guided in the first and second flux collectors; d) the amount of the first disturbing magnetic flux contained in the superposition of the signal magnetic flux and the first disturbing magnetic flux, which is sensed substantially in the first sensing direction, is reduced or substantially eliminated by scaling the amount of the second disturbing magnetic flux sensed in the second sensing direction and by subtracting the scaled signal from the superposition of the signal magnetic flux and the first disturbing magnetic flux.

Scaling may be performed in the analog domain or the digital domain. (commonly referred to as "amplification" in the analog domain and "multiplication" in the digital domain). The scaling may be performed using a predefined scaling factor.

According to a fourth aspect, the present invention provides a method of determining a signal magnetic flux generated by a signal magnetic field source and optionally modulated by a magnetic structure in a manner substantially immune to a magnetic interference field, comprising the steps of: a) providing a magnetic field sensor arrangement according to the first aspect; b) measuring, by the magnetic field sensor, a first signal of a magnetic field component oriented in a first direction; c) measuring, by the magnetic field sensor, a second signal of a magnetic field component oriented in a second direction perpendicular to the first direction; d) if a magnetic interference field is present, the effect of the magnetic interference field is reduced or substantially eliminated based on the measured first magnetic field component and the measured second magnetic field component.

Again, it is noted that with regard to the effects and advantages of the features relating to the method disclosed herein, reference is made in its entirety to the corresponding similar features of the magnetic field sensor arrangement and/or the angle sensor arrangement and/or the magnetic torque sensor arrangement disclosed herein, and to the effects and advantages thereof. Thus, unless explicitly stated otherwise, features of the magnetic field sensor arrangement and/or features of the angle sensor arrangement and/or features of the magnetic torque sensor arrangement disclosed herein should also be considered as applicable to the defined features of the method for determining a signal magnetic flux according to the present invention. Likewise, unless explicitly stated otherwise, features of the method disclosed herein shall also be considered as applying to the defined features of the magnetic field sensor arrangement and the magnetic torque sensor arrangement, respectively, according to the present invention. Therefore, for the purpose of simplicity and clarity of this description and to enhance the comprehension of the principles of the present invention, repetition of the explanation of such similar features, effects and advantages thereof is hereinafter largely omitted.

In an embodiment, step d) comprises: the second signal is scaled by a predefined constant and the scaled signal is subtracted from the first signal.

In an embodiment, step d) is performed by a processor unit and a memory unit integrated in the magnetic field sensor.

In an embodiment, step a) comprises: a) providing an angle sensor arrangement according to the second aspect; and wherein the method further comprises the steps of: e) the corrected first signal is converted into an angular distance value.

This method is in fact a method of determining the angle in a way that is highly insensitive to magnetic interference fields.

Step e) may comprise: using a mathematical expression or a look-up table.

In an embodiment, step a) comprises: a) providing a torque sensor arrangement according to the third aspect; and the method further comprises the steps of: e) the corrected first signal is converted into a torque value.

This method is in fact a method for determining the torque in a way that is highly insensitive to magnetic interference fields.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from dependent claims may be combined with features of the independent claims and features of other dependent claims as appropriate and not merely as explicitly set out in such claims.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Drawings

Fig. 1(a) and 1(b) show a side view and a front view, respectively, of an embodiment of a magnetic field sensor arrangement known in the art.

Fig. 2(a) and 2(b) show a side view and a front view, respectively, of an exemplary embodiment of a magnetic field sensor arrangement and an angle sensor arrangement according to the present invention.

Fig. 3(a) and 3(b) and 3(c) show enlarged views of an embodiment of the invention showing a portion of the magnetic field sensor arrangement shown in fig. 2 (a). The sensor device of fig. 3(a) is horizontally oriented and contains two horizontal hall elements and an Integrated Magnetic Concentrator (IMC). The sensor device of fig. 3(b) is vertically oriented and contains two horizontal hall elements and an IMC. The sensor device of fig. 3(c) is vertically oriented and contains a horizontal hall element and a vertical hall element.

Fig. 4(a) and 4(b) show views similar to fig. 3(a) to 3(c), but showing views of further exemplary embodiments of the magnetic field sensor arrangement according to the present invention. The sensor device of fig. 4(a) is horizontally oriented and contains a horizontal hall element and a vertical hall element. The sensor device of fig. 4(b) is vertically oriented and contains two vertical hall elements.

Fig. 5 shows a side view of another exemplary embodiment of a magnetic field sensor arrangement according to the present invention, which can be seen as a variant of the magnetic field sensor arrangement of fig. 2, wherein one of the yokes has a protruding portion for defining an air gap. The sensor device is represented by a black rectangle. Any of the sensor devices of fig. 3(a) to 4(b) may be used.

Fig. 6(a) and 6(b) show side and front views, respectively, of the magnetic field sensor arrangement shown in fig. 2, depicting the course of a first portion of the magnetic flux lines generated by an external interfering magnetic field source (located at the top of fig. 6). The first part passes through the air gap in the gap direction (radial with respect to the magnetic structure).

Fig. 7(a) and 7(b) show the same arrangement as fig. 6, but now showing the process of the second portion of the lines of magnetic flux generated by the source of the disturbing magnetic field. The second portion passes through the air gap in a direction perpendicular to the direction of the gap.

Fig. 8(a) and 8(b) show side and front views, respectively, of the magnetic field sensor arrangement shown in fig. 2, depicting the course of magnetic flux lines generated by another external interfering magnetic field source (located at the left part of fig. 8). These flux lines do not cross the air gap (not in the radial direction, not in the axial direction).

Fig. 9(a), 9(b) and 9(c) show a perspective view, a side view and a front view, respectively, of the magnetic field sensor arrangement and the angle sensor arrangement shown in fig. 2.

Fig. 10(a) and 10(b) show a side view and a front view, respectively, of another exemplary embodiment of a magnetic field sensor arrangement according to the present invention.

Fig. 11(a), 11(b) and 11(c) show a perspective view, a side view and a front view, respectively, of the magnetic field sensor arrangement and the angle sensor arrangement shown in fig. 10.

Fig. 12 shows a flow chart of a method of determining a signal magnetic flux generated by a signal magnetic field source and optionally modulated by a magnetic structure in a manner that is highly immune to an interfering field according to an embodiment of the invention.

The drawings are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. Any reference signs in the claims shall not be construed as limiting the scope. In the various figures, elements that are functionally equivalent thereto have always been provided with the same reference symbols, and these elements are therefore generally described only once.

Detailed Description

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and relative dimensions do not correspond to actual reductions to the invention.

Moreover, the terms first, second, and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential order temporally, spatially, in ranking, or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Furthermore, the terms top, bottom, and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term 'comprising', used in the claims, should not be interpreted as being limitative to the means listed thereafter; it does not exclude other elements or steps. Accordingly, the terms should be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "an apparatus comprising device a and device B" should not be limited to an apparatus consisting of only part a and part B. It means that the only relevant components of the device in respect of the present invention are a and B.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments as will be apparent to one of ordinary skill in the art in view of the present disclosure.

Similarly, it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention.

Furthermore, as will be understood by those of skill in the art, although some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the appended claims, any of the claimed embodiments can be used in any combination.

In the description provided herein, numerous specific details are set forth. It is understood, however, that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

In this document, the terms "magnetic interference field" and "magnetic stray field" are considered as synonyms. They will be used interchangeably herein and refer to substantially the same subject matter, unless explicitly stated otherwise.

In this document, the expressions "immune to stray fields" and "highly insensitive to external disturbing fields" and "highly robust to external disturbing fields" mean the same.

In this document, the expressions "determined immunologically for the stray field" and "determined immunologically for the stray field" mean the same.

In this document, the terms "(external) magnetic field concentrator" or "magnetic flux guide" or "magnetic yoke" mean the same.

In this document, the terms "magnetic field sensor" and "magnetic sensor device" or "sensor device" mean the same. The magnetic sensor device comprises a semiconductor substrate with at least two magnetic sensor elements (e.g. hall elements). The magnetic sensor device may be encapsulated in a molded package, but this is not absolutely necessary.

In the present document, the magnetic field sensor arrangement may be associated with a first orthogonal coordinate system X, Y, Z having an axial direction (denoted Z), a radial direction (denoted X) across the air gap, and a circumferential direction Y (e.g. as depicted in fig. 2a and 2 b).

In this document, the semiconductor plane of the magnetic field sensor may be associated with a second orthogonal coordinate system U, V, W, where the U and V axes are parallel to the semiconductor plane and the W axis is perpendicular to the semiconductor plane.

The expression "signal magnetic field" or "signal magnetic flux" as used herein refers to a (desired) signal or magnetic flux, respectively, originating from a "signal magnetic field source" (e.g. a multi-pole ring magnet) as part of a magnetic arrangement. The signal and the magnetic flux are used as measurement signals, for example to determine an angular displacement between two shaft parts (e.g. of a steering column or the like) in a contactless manner.

In this document, the term "signal magnetic field source" refers to a "magnetic source", e.g. one or more permanent magnets, a magnetically arranged part, e.g. a radially magnetized multi-pole ring magnet.

In this document, the terms "magnetic field sensor arrangement" or "magnetic structure" are used as synonyms.

In this document, the term "magnetic field sensor" or "magnetic sensor device" refers to a device comprising at least two magneto-sensitive elements, unless explicitly stated otherwise. The sensor device may be comprised in a package (also referred to as "chip"), but this is not absolutely necessary. In an embodiment of the present invention, a magnetic sensor includes a semiconductor substrate. The at least two magneto-sensitive elements may be integrated in the substrate.

In the present document, the term "sensor element" or "magnetic sensor element" or "sensor" may refer to a component or a set of components or sub-circuits or structures capable of measuring a magnetic quantity, such as, for example, a magnetoresistive element, an XMR element, a horizontal hall plate, a vertical hall plate, a wheatstone bridge comprising at least one (but preferably four) magnetoresistive element, a structure comprising a disk-shaped magnetic concentrator and two or four horizontal hall elements arranged near the periphery of the disk, etc.

Fig. 1(a) and 1(b) show a side view and a front view, respectively, of a torque sensor 100 comprising a magnetic structure 110 and a magnetic field sensor arrangement 120 as known in the art. The sensor arrangement 120 is configured to determine a signal magnetic flux (not specifically indicated) generated by a signal magnetic field source S1, such as a radially magnetized multi-pole ring magnet (not explicitly shown). The sensor arrangement 120 may also be considered a "readout portion" of the torque sensor 100.

However, the torque sensor 100, or in particular the sensor arrangement 120, is not immune to external disturbing magnetic fields or magnetic flux (not shown in fig. 1, but see e.g. fig. 6 to 8) generated by an external disturbing magnetic field source S2 (e.g. one or more nearby current conductors carrying currents, in particular strong currents, such as several tens of a or even more than 100A). Although strictly speaking such currents do not produce a uniform field (i.e. constant orientation and amplitude), in practice, the magnetic interference field may be considered "substantially uniform" in a relatively small space at a sufficient distance from the conductor (e.g. at a distance of at least 10cm, or at least 20cm from the current conductor).

The prior art sensor arrangement 120 comprises a first magnetic flux concentrator 101 and a second magnetic flux concentrator 102 (also referred to as a yoke or a magnetic flux guide). An air gap 103 is formed between the outer face 104 of the first flux concentrator 101 and the outer face 105 of the second flux concentrator 102. There is a direct line of sight between the first and second outer faces 104, 105. The "gap direction" 106 may be defined by a line of shortest length (or a line of shortest distance) between the two

outer faces

104, 105 of the first and

second flux concentrators

101, 102. In the arrangement of fig. 1(a), the "gap direction" is oriented in the Z-direction (i.e., in the axial direction of the magnetic structure 110). Furthermore, a magnetic field sensor 107 (schematically indicated by a black rectangle) is arranged in the air gap 103. The magnetic field sensor 107 of the sensor arrangement 120 shown in fig. 1 is sensitive to the magnetic field component Bz in the Z-direction (i.e. in the axial direction of the structure 110).

The torque sensor 100 of fig. 1 further includes a magnetic structure or magnetic arrangement 110 that includes a signal magnetic field source S1, such as a radially magnetized multi-pole ring magnet, that generates a signal magnetic flux (not shown). The magnetic structure 110 is configured and arranged such that the signal magnetic flux is modulated as a function of the relative angular displacement between the first magnetic ring 111 and the second magnetic ring 112 surrounding the signal magnetic field source S1. As depicted in fig. 1, the two

magnetic rings

111, 112 have respective toothed or fin-shaped protrusions 113, 114 (also referred to as "teeth" or "claws" or "pads") arranged along the periphery of each

magnetic ring

111, 112, the free ends of which point towards each other in an opposing manner. The

protrusions

113, 114 of the first ring 111 and the second ring 112 extend substantially in the direction of a common axis of rotation 115 of the two

rings

111, 112. Magnetic field source S1 is disposed on shaft 115 between the center of first ring 111 and the center of second ring 112.

Thus, the

unshaded parts

111, 112, 113, 114, S1 are considered to be part of the "magnetic structure" 110, while the shaded

parts

101, 102 and the sensor 107 are considered to be part of the "(magnetic field) sensor arrangement" 120. This combination of a magnetic structure 110 and a sensor arrangement 120 as shown in fig. 1 is known to be used as a magnetic torque sensor arrangement 100 for determining a torque applied to a torque rod (not shown in fig. 1) that elastically connects (e.g., by a torsion bar) an end of a first shaft (also referred to as an input shaft) to an end of a second shaft (also referred to as an output shaft). Further details of various embodiments of such combinations are disclosed, for example, in the above-mentioned documents DE10222118a1 or EP 3505894.

Furthermore, the signal magnetic flux generated by the signal magnetic field source S1 of the magnetic torque sensor arrangement shown in fig. 1 is received by the first and

second flux concentrators

101, 102 and is guided to the air gap 103 substantially in the gap direction 106(═ Z direction) within the first and

second flux concentrators

101, 102, wherein the signal magnetic flux is sensed by the magnetic field sensor 107.

Now, if there is an interfering magnetic flux generated by the interfering magnetic field source S2 substantially in the Z-direction, this magnetic flux will also be captured/received by the first and

second flux concentrators

101, 102 and guided within the first and

second flux concentrators

101, 102 to be superimposed and added to the signal magnetic field within the two

flux concentrators

101, 102. Thus, the torque sensor 100 comprising the sensor arrangement 120 shown in fig. 1 is not immune (or robust) to the (external) disturbing magnetic flux generated by the (external) disturbing magnetic field source S2, since the magnetic field sensor 107 cannot distinguish between the signal magnetic flux directed to the air gap 103 and the disturbing magnetic flux.

Fig. 2(a) and 2(b) show side and front views, respectively, of an exemplary embodiment of a torque sensor arrangement 200 comprising the magnetic structure 110 of fig. 1 but comprising a modified sensor arrangement 220. In general, the torque sensor 200, and in particular the magnetic field sensor arrangement 220, is capable of determining, in a stray field immune manner, a signal magnetic flux generated by the signal magnetic field source S1 (e.g., a radially magnetized multi-pole ring magnet) and optionally modulated by the magnetic structure 110.

In fig. 2, the magnetic field sensor arrangement 220 is also shown in combination with the magnetic structure 110 (or the magnetic arrangement 110) as depicted in fig. 1. Thus, the combination of the magnetic field sensor arrangement 220 and the magnetic arrangement 110 may form a magnetic torque sensor arrangement 200 for stray field immunologically determining the torque applied to a torque rod (not shown).

As shown in fig. 2, the magnetic field sensor arrangement 220 comprises a first magnetic flux concentrator 201 and a second magnetic flux concentrator 202 (also referred to as magnetic flux guide or yoke). The flux concentrators 201, 202 are configured and arranged such that an air gap 203 is formed between an outer face 204 of the first flux concentrator 201 and an outer face 205 of the second flux concentrator 202. The two

outer faces

204, 205 are the respective outer faces of the first and

second flux concentrators

201, 202, respectively, with a minimum distance between them, and the "gap direction" 206 of the air gap 203 is defined by the line of shortest length (or shortest distance) between the first and second outer faces 204, 205. The magnetic field sensor (or sensor device) 207, indicated by a black rectangle, is configured to be sensitive to magnetic fields in at least a first sensing direction X and a second sensing direction Z, wherein the first sensing direction X and the second sensing direction Z are substantially perpendicular to each other.

More specifically, the X direction is oriented substantially radially with respect to the magnetic structure 110 (and therefore perpendicular to the axis 115 and preferably intersecting the axis 115), and the Z direction is substantially parallel to the axis 115 (and therefore parallel to the torsion bar, if present). In other words, the X-direction lies substantially in an imaginary plane X-Y perpendicular to said axis 115.

Furthermore, the first and

second flux concentrators

201, 202 are further configured and arranged such that a first portion 228 (see fig. 6(a)) of the signal magnetic flux generated by the signal magnetic field source S1 and the disturbing magnetic flux generated by the disturbing magnetic field source S2 different from the signal magnetic field source S1 will be received by the first and

second flux concentrators

201, 202 and substantially in the air gap direction 206 within the first and

second flux concentrators

201, 202 leading in a radial direction X into and through the air gap 203. A second portion 229 of the disturbing magnetic flux generated by the disturbing magnetic field source S2 (see fig. 6(a)) will pass through the air gap 203 without being received by the first and

second flux concentrators

201, 202 and being guided to the air gap 203 within the first and

second flux concentrators

201, 202. This is an important aspect of the present invention and will be explained in more detail further on.

As described above, if the torque sensor 200 is sufficiently far away from the external source of interference S2 (e.g., at least 10cm, or at least 20cm, or at least 30cm), the external interference field can be considered substantially uniform, particularly "inside the air gap". The magnetic field sensor 207 is arranged in the air gap 203 such that it is able to sense a combination of the signal magnetic flux and a first portion of the disturbing magnetic flux traversing the air gap in the first direction X and a second portion of the disturbing magnetic flux traversing the air gap in the second direction Z. Depending on the orientation of the sensor device, the X-direction and the Z-direction may be parallel or orthogonal to the semiconductor substrate, as will be further described (in fig. 3(a) to 4 (b)).

An "air gap space" may be defined as a 3D space between first and second outer faces 204, 205 described above, and more specifically, a 3D space between corresponding points of these faces for which the distance is substantially equal to the "minimum distance" within a small tolerance margin (e.g., +/-10% or +/-5%). In the example of fig. 2, the 3D space has a length 206 (in the X-direction) equal to the "gap length" and has a cross-sectional area (in the Y-Z plane) defined by the shape of the first and second outer faces 204, 205 (e.g., by the overlap of the projections of these outer faces in the gap direction on the Y-Z plane). In the example of fig. 2, the overlap is substantially rectangular, having a width 209 (see fig. 2(b)) and a height 210 (see fig. 2 (a)). Thus, in the example of fig. 2, the "air gap space" or "air gap space" is substantially beam-shaped, but may also be substantially cubic.

Preferably, the sensor device 207 is arranged substantially inside the air gap 203, in the sense that all magneto-sensitive elements (e.g. hall elements and/or IMCs) of the magnetic sensor 207 are located inside the air gap space.

Fig. 3(a) and 3(b) show enlarged views of two embodiments of a portion of the magnetic field sensor arrangement 220 shown in fig. 2, in particular a portion close to the air gap 203.

In the embodiment of fig. 3(a), the semiconductor substrate of the magnetic sensor device 207a is oriented substantially parallel to the X-Y plane, i.e. parallel to the gap direction 206, and perpendicular to the axial direction Z.

Assuming that a second coordinate system having axes U, V, W is associated with the sensor device 207a such that the semiconductor substrate is parallel to the UV plane and orthogonal to the W axis, the U axis of the sensor device corresponds to the X axis of the magnetic structure, the V axis of the sensor device corresponds to the Y axis of the magnetic structure, and the W axis of the device corresponds to the Z axis of the magnetic structure. Thus, it is stated that the sensor device needs to be sensitive in the X-direction and the Z-direction with respect to the magnetic structure, which is equivalent to the explanation that the sensor device 207a needs to be sensitive in the U-direction and the W-direction.

The sensor device 207a depicted in fig. 3a comprises an Integrated Magnetic Concentrator (IMC)211 and two

horizontal hall elements

212a, 212b arranged near the periphery of the IMC. Such sensor structures are known in the art and are capable of measuring a (so-called "out-of-plane") magnetic field component Bw oriented perpendicular to the semiconductor substrate, and a (so-called "in-plane") magnetic field component Bu oriented parallel to the semiconductor substrate. Readers unfamiliar with such sensor structures can find more information in, for example, patent publication US2018372475(a1) (see fig. 4(a) to 4(c)) or patent application EP3505894a1 filed by the same applicant on 21.12.2018, particularly fig. 6 and 7(a, b, c), both of which are incorporated herein by reference in their entirety. Note, however, that other suitable sensor devices capable of measuring two orthogonal magnetic field components may also be used. The sensor device 207 needs to be oriented such that it is able to measure two orthogonal magnetic field components, one oriented in the gap direction 206 (corresponding to the X-direction of the magnetic structure) and the other perpendicular to the gap direction (corresponding to the Z-direction of the magnetic structure).

Referring to fig. 3(a) of the present invention, the sensor device 207a is oriented such that its semiconductor substrate is perpendicular to the Z-axis. The sensor device 207a includes an Integrated Magnetic Concentrator (IMC)211 (e.g., a disk-shaped IMC) and two

horizontal hall elements

212a, 212b located near the periphery of the IMC. The sensor device 207a is capable of measuring an out-of-plane magnetic field component Bw (oriented in the Z-direction of the magnetic structure) and an in-plane magnetic field component Bu (oriented in the X-direction of the magnetic structure).

The Bw signal may be determined, for example, by summing the signals obtained from the two

hall elements

212a, 212 b. The Bu signal may be determined, for example, by subtracting the signal from two hall elements. In this orientation of the sensor device 207a, the Bu signal indicates a superposition of the signal magnetic flux and a first portion 228 (see fig. 6a) of the interfering magnetic flux (if present), and the Bw signal indicates only a second portion 229 of the interfering magnetic flux. In this orientation of the sensor device 207a, the Bu signal is passively amplified by the presence of the integrated magnetic concentrator 211. However, this orientation is not ideal because (i) the width of the substrate is typically greater than its thickness, and therefore the gap distance needs to be relatively large in order to fit the sensor device 207a, and (ii) the second portion 229 of the interfering magnetic flux is typically very weak, but not magnified by the flux concentrator.

Referring to fig. 3(b), the sensor device 207b may be the exact same sensor device as the sensor device 207a of fig. 3(a), but rotated 90 ° about the Y-axis. The sensor device 207a is capable of measuring an out-of-plane magnetic field component Bw oriented in the X-direction of the magnetic structure and an in-plane magnetic field component Bu oriented in the Z-direction of the magnetic structure. In this orientation of the sensor device 207b, the Bw signal indicates a superposition of the signal magnetic flux and the first interference portion 228 (not amplified by the IMC); and the Bu signal is indicative of the second interfering portion 229, and the Bu signal is passively amplified by the IMC.

An advantage of this embodiment is that the gap distance 206 of fig. 3(b) may be less than the gap distance 206 of fig. 3 (a). This is not only true for packaged sensor devices, but also for unpackaged sensor devices, since the substrate thickness is typically much smaller than the substrate width. In addition, the semiconductor substrate thickness can be further reduced by a process called "wafer thinning". In this case, a substrate having a thickness of less than 500 μm or less than 400 μm or less than 300 μm may be used. The use of a smaller gap distance 206 has a positive effect on the magnetic flux density and thus on the signal-to-noise ratio and thus on the accuracy of the signal. Another advantage is that the (weak) second disturbing part 229 is passively amplified by the IMC.

Or in other words, one particular advantage of the magnetic field sensor 207b with respect to this "vertical arrangement" of the "horizontal arrangement" shown in fig. 3(a) is that the magnetic gain provided by the internal flux concentrator 211 can be used to amplify the (disturbing) magnetic flux Bz entering the air gap 203 in the Z-direction, as opposed to the magnetic flux Bx entering the air gap 203 in the X-direction, which magnetic flux Bx has been (externally) amplified by the two flux concentrators (or yokes) 201, 202.

However, the present invention is not limited to the examples shown in fig. 3(a) and 3(b), and other sensor devices, for example, a sensor device including a magnetoresistive element, may also be used.

Fig. 3(c) shows a variation of the sensor arrangement of fig. 3 (b). The sensor device 207c of fig. 3(c) is also oriented "vertically" (i.e., its semiconductor substrate is parallel to the Y-Z plane), but contains a horizontal hall element 212c and a vertical hall element 212 d. The horizontal hall element 212c is configured to measure a first magnetic field component in the W direction with respect to the substrate corresponding to the radial direction of the magnetic structure, and a second magnetic field component in the U direction corresponding to the axial direction of the magnetic structure.

This embodiment has the advantage of not requiring IMC and a small gap distance, but does not provide passive amplification of the second fringe field portion 229 (not shown, but across the air gap in the axial direction Z).

Fig. 4(a) and 4(b) show views similar to fig. 3, but showing other exemplary embodiments of a magnetic field sensor arrangement (not shown in its entirety) according to the present invention. In these embodiments, the

magnetic field sensors

213a, 213b comprise at least one sensing element 214, such as for example a magneto-resistive element, an XMR element, a vertical hall plate, a wheatstone bridge comprising at least one magneto-resistive element, etc., the magnetic field sensors 213, 213b being sensitive to each of the at least two sensing directions X, Z (with respect to the magnetic arrangement) or U, V (with respect to the semiconductor substrate). The sensor device 213 of fig. 4 does not contain an integrated magnetic field concentrator (IMC).

More specifically, in the embodiment of fig. 4(a), the semiconductor substrate is oriented "horizontally" (i.e., the substrate is parallel to the X-Y plane and the substrate thickness is in the Z direction), and sensor element 214a is a vertical hall element configured to measure Bx and sensor element 214b is a horizontal hall element configured to measure Bz.

In the embodiment of fig. 4(b), the semiconductor substrate is oriented "vertically" (substrate parallel to the X-Z plane, substrate thickness in the Y direction), the sensor element 216a is a vertical hall element configured for measuring the signal Bx (containing the combination of the desired signal and the first interfering portion 228), and the sensor element 216b is a vertical hall element configured for measuring the signal Bz (containing only the second interfering portion 229).

In some embodiments of the invention, wherein at least two sensor elements are used in the magnetic field sensor, the sensor elements may have different sensitivities to the magnetic field to be detected. For example, different sensitivities may be achieved by using different sensor technologies and/or different sensor configurations described above (e.g., with/without an internal flux concentrator), by using different biasing devices (e.g., voltage or current), by using different electronic gains, and so forth.

Note that the magnetic field sensors 207, 213 shown in fig. 3 and 4, respectively, may each be provided as a single semiconductor substrate, optionally packaged in a single chip package. Although not shown, the substrate and/or the chip package may also include a processor unit (e.g., a microprocessor or microcontroller) and a memory unit (e.g., volatile and/or non-volatile memory, such as RAM, ROM, flash memory, etc.), as described herein. The processor, memory, etc. need not be located inside the air gap, but it is important that the magneto-sensitive element is located inside the air gap.

In a preferred embodiment of the invention, the sensor device is configured for determining the magnetic flux generated by the first magnetic field source S1 and modulated by the magnetic structure 110 by performing the following steps:

a) measuring a first magnetic field component Bx oriented in the gap direction (radial to the magnetic structure 110);

b) measuring a second magnetic field component Bz oriented in a direction perpendicular to the gap direction (axial direction of the magnetic structure 110);

c) the second signal is multiplied by a predefined constant K to obtain an estimate of the first interference portion 228. The value of K may be hard coded or stored in non-volatile memory;

d) subtracting said estimates of the first signal and the first interference portion, thereby reducing or substantially eliminating the influence of an external interference field which is considered to be substantially uniform at least inside the air gap.

Depending on the application (e.g. angle sensor or torque sensor application) the method may comprise a further step e) of demodulating the subtraction result, e.g. using a look-up table, optionally with linear interpolation.

Fig. 5(a) shows a side view of another exemplary embodiment of an angle sensor or torque sensor 500 comprising a magnetic field sensor arrangement 240 according to the present invention. Compared to the magnetic field sensor arrangement 220 shown in fig. 2, the magnetic field sensor arrangement 240 of fig. 5 comprises a first magnetic flux concentrator 221 having a slightly different configuration near the air gap 203, as will be described below.

In fig. 2, this outer face 204 is the area located on the side of the vertically oriented leg portion 224 of the first flux concentrator 221, where the flux lines (not shown) cross the air gap, which in practice means at the position where the distance to the outer surface 205 of the second flux concentrator 202 is minimal. In this case, the outer face region 204 is not explicitly defined.

In fig. 5(a), the outer face 204 of the first flux concentrator 221 is also provided on the portion 223 of the first flux concentrator 221, which is located where the field lines will leave the first flux concentrator 201, which in practice means at a location where the distance to the outer surface 205 of the second flux concentrator 202 is minimal, but in this case the boundary of this outer face 204 is precisely defined by a protrusion 226 or a bend 226 or the like extending radially outwards with respect to the first flux concentrator 221.

As can be seen, the first magnetic concentrator 221 of fig. 5(a) has a Z-shape (in a cross-sectional plane parallel to the X-Z plane). More specifically, the first flux concentrator 221 (or yoke) has a protrusion or curved portion directed towards the air gap 203. Thus, the outer face 204 is clearly defined and is located at the end of the protrusion or curved portion.

Fig. 5(b) shows another angle or torque sensor 550 that is a variation of the angle or torque sensor 500 of fig. 5 (a). The magnetic structure 110 is the same as that of fig. 2 and 5(a), but the sensor arrangement 250 is slightly different. In this case, the first yoke 251 disposed adjacent to the first ring 111 extends further outward in the radial direction than the second yoke 252. It is important, however, that also in this case the gap direction 206 is oriented in a radial direction X with respect to the magnetic structure 110 between the first face 204 on the first magnetic concentrator 251 and the second face 205 on the second magnetic concentrator 252.

It will be appreciated by persons having the benefit of the present disclosure that fig. 5(a) and 5(b) are two examples, wherein the air gap 203 is located at substantially the same axial position as the lower ring 112, but of course the invention is not limited thereto and the air gap 203 may also be located at a different axial position, e.g. substantially midway between the first ring 111 and the second ring 112, which may be achieved by reducing the length of the vertical (axial) leg 224 of the

first concentrator

201, 221, 251 and by increasing the vertical (axial) leg of the

second concentrator

202, 252 such that the gap direction 206 of the air gap 203 between them is oriented in the radial direction X.

Although not explicitly shown, this is of course the case in fig. 2. Also here, the position of the air gap 203 can be moved in the axial direction by making the vertical leg 224 (extending in the Z direction) shorter and by making the vertical leg 202 (extending in the Z direction) longer.

Furthermore, although not explicitly shown in fig. 5(a) and 5(b), the sensor device 207 may be arranged inside the air gap in a manner similar to that shown in any of fig. 3(a) to 4 (b).

Fig. 6(a) and 6(b) show a side view and a front view, respectively, of the angle sensor arrangement or magnetic torque sensor arrangement 200, and the magnetic field sensor arrangement 220, shown in fig. 2, furthermore depicting the course of the magnetic flux lines 227a caused by the first portion 228 of the magnetic field generated by the external disturbing magnetic field source S2 and oriented in the Z-direction at the location of the torque sensor arrangement.

As shown, a first portion 228 of the external magnetic interference field generated by the interfering magnetic field source S2 is received by the first and

second flux concentrators

201, 202 and guided in the first and

second flux concentrators

201, 202 substantially in the air gap direction 206 into and through the air gap 203, wherein the first portion is sensed by the magnetic field sensor 207 through one or more sensor elements sensitive in the X-direction. In fact, the signal sensed in the X-direction is not only the first disturbance component 228, but also a superposition of the (unwanted) first disturbance component 228 and the (wanted) signal magnetic flux generated by the signal magnetic field source S1 (e.g. by a radially oriented multipole ring magnet located substantially midway between the first ring 111 and the second ring 112) and optionally modulated by the magnetic structure 110. The sensor device 207 is not able to distinguish between a (wanted) signal flux and a (unwanted) disturbing flux based on the signal measured in the X-direction only.

Fig. 7(a) and 7(b) show a side view and a front view, respectively, of the magnetic torque sensor arrangement 200 and the magnetic field sensor arrangement 220 shown in fig. 2, furthermore depicting the course of the magnetic flux lines 227b caused by the second part 229 of the magnetic field generated by the external disturbing magnetic field source S2 and oriented in the Z-direction at the location of the torque sensor arrangement.

The second portion 229 is not received by the first and

second flux concentrators

201, 202 and is guided into the air gap 203 within the first and

second flux concentrators

201, 202. In contrast, a second interfering magnetic flux 229 traverses the air gap 203 in a Z-direction (i.e., an axial direction of the magnetic structure) perpendicular to the X-direction. The second disturbing magnetic flux 229 is sensed by the magnetic field sensor 207 through one or more sensor elements sensitive in the Z-direction. In this way, the amount of external interfering magnetic flux 229 present in the vicinity of the magnetic structure 200 and the field sensor arrangement 220 may be determined (e.g., measured) independently of the external interfering magnetic flux 228 flowing within the first and second

magnetic flux concentrators

201 and 202. Since the first portion 228 and the second portion 229 are from the same source S2, the amplitudes of the first portion 228 and the second portion 229 are correlated. The correlation may be approximated by a predefined factor. The predefined factor is independent of the magnitude of the external disturbing field, but mainly related to the shape, size and material of the magnetic arrangement 200 (comprising the magnetic structure 110 and the magnetic sensor arrangement 220), and may be determined by design, by simulation, by calibration, or in any other suitable way. The predefined factor may be hard-coded in a program executed by the microcontroller or may be stored in a non-volatile memory of the sensor device.

Therefore, the total magnetic flux (which is the superposition of the desired signal and the first interference portion) sensed by the magnetic sensor 207 in the X direction can be corrected by a simple arithmetic operation, more specifically, by scaling the magnetic signal Bz sensed by the magnetic sensor 207 in the Z direction by a predefined factor, and by subtracting the scaled signal from the magnetic signal Bx sensed by the magnetic sensor 207 in the X direction. Note that the actually used scaling factor may also take into account the sensitivity difference in the X-direction and the Z-direction of the sensor device (e.g. due to IMC amplification), and/or the amplification factor caused by the first and

second flux concentrators

201, 202. Thus, the interference fields can be reduced or substantially eliminated in a surprisingly simple manner.

Furthermore, it is to be noted that the disturbing

magnetic flux

228, 229 generated by the external disturbing magnetic field source S2 may originate from a homogeneous or homogeneous disturbing magnetic field or from a non-homogeneous field source (e.g. current wires) which is located at a sufficient distance (e.g. at least 10cm or at least 20cm) from the magnetic sensor arrangement.

In fig. 6 and 7, the influence from an external disturbing field oriented in the Z-direction is depicted. As explained, this can be greatly reduced or eliminated altogether.

Although not explicitly shown, it is understood that an external disturbing field oriented in the Y-direction has no influence on the measurement, because the first part of the disturbing field received by the first and second flux concentrators in the Y-direction will also leave the first and second flux concentrators in the Y-direction without crossing the air gap, and because the sensor device itself is insensitive to magnetic fields passing through the air gap in the Y-direction.

Fig. 8(a) and 8(b) show side and front views, respectively, of the magnetic torque sensor arrangement 200 and the magnetic field sensor arrangement 220 shown in fig. 2, further depicting the process of the magnetic flux lines 227 generated by the external disturbing magnetic field source S3 (located on the left side of fig. 8) generating a disturbing field oriented in the X-direction.

As is apparent from fig. 8, the disturbing magnetic flux 230 oriented in the X-direction does not substantially (or at most to a small, negligible extent) enter the air gap 203, because most of the flux lines enter the

rings

111, 112, but leave the magnetic structure via the vertical legs of the first and

second flux concentrators

201, 202. Only a small part of the magnetic flux entering the first ring 111 will pass through the air gap and leave the sensor structure via the second flux concentrator 202, and therefore it does not substantially contribute to the total magnetic flux sensed by the magnetic field sensor 207 in the X-direction.

Since the uniform interference field oriented in any direction can be decomposed into three orthogonal components, one oriented in the Z direction, one oriented in the X direction, and one oriented in the Y direction, it can be understood from the above that the signal magnetic flux generated by magnetic source S1 (e.g., a multi-pole ring magnet) can be measured in a manner that is highly robust to external interference fields oriented in any direction, since the interference magnetic flux in the Z direction passes through the air gap but is compensated for, the interference magnetic flux oriented in the Y direction does not pass through the air gap, and the interference magnetic flux in the X direction does not pass through or significantly passes through the air gap, and thus does not affect or does not significantly affect the measurement of the signal generated by first magnetic source S1.

Fig. 9(a), 9(b) and 9(c) show perspective, side and front views, respectively, of the magnetic field sensor arrangement 220 shown in fig. 2 suitable for use in combination with the magnetic arrangement 110 as the angle sensor and/or magnetic torque sensor arrangement 200 as disclosed herein. The magnetic arrangement 110 comprises a radially magnetised multi-pole ring magnet S1, and may further comprise a torsion bar (not shown), for example similar or identical to that described in DE10222118a1 or EP3505894a 1.

Fig. 10(a) and 10(b) show a side view and a front view, respectively, of yet another exemplary embodiment of an angle sensor arrangement and/or a magnetic torque sensor arrangement 300 comprising a magnetic structure 110 and a magnetic field sensor arrangement 320 as described above.

The main difference between this embodiment and the magnetic field sensor arrangement 220 of fig. 2 is that the outer face 204 of the first magnetic flux concentrator 301 is provided on a portion 303 of the first magnetic flux concentrator 301, which portion 303 comprises one fin-shaped extension member 304, and the outer face 205 of the second magnetic flux concentrator 302 is provided on a portion 305 of the second magnetic flux concentrator 302, which portion 305 comprises three fin-shaped

extension members

306, 307, 308, wherein the fin-shaped

extension members

304, 306, 307, 308 extend in a direction oriented substantially perpendicular to the gap direction 206 and exceed the width 209 and/or the height 210 of the cross section of the air gap 203 in a plane perpendicular to the gap direction 206.

Fig. 11(a), 11(b) and 11(c) show perspective, side and front views, respectively, of the magnetic torque sensor arrangement 300 and the magnetic field sensor arrangement 320 used in combination with the magnetic arrangement 110 of fig. 10.

FIG. 12 illustrates a flow diagram of a method 1200 for stray field immunologically determining the signal magnetic flux generated by the signal magnetic field source S1 in a manner that is highly immune to interfering fields. The method comprises the following steps:

a) providing 1201 a magnetic structure 110 comprising a magnetic source S1 and two

magnetic concentrators

111, 112, the

magnetic concentrators

111, 112 being configured for guiding a magnetic flux generated by the source and forming an air gap 203 oriented in a radial direction X with respect to the magnetic structure 110;

b) measuring 1202 inside the air gap 203 a first magnetic field component Bx oriented in a radial direction X, the first magnetic field component Bx being indicative of a combination of a signal generated by the magnetic source S1 and the first portion 228 of the disturbing field S2 oriented in an axial direction Z with respect to the magnetic structure 110;

c) measuring 1203 a second magnetic field component Bz oriented in the axial direction Z of the magnetic structure 110 inside the air gap 203, the second magnetic field component Bz being indicative of a second portion 229 of said disturbing field S2 oriented in the axial direction Z with respect to the magnetic structure 110;

d) the first interference portion 228 is reduced or eliminated 1204 by scaling the second signal Bz by a predefined constant K and by subtracting the scaled signal from the first signal Bx.

The method 1200 may further comprise step e): the corrected first signal is converted 1205 into an angular distance value and/or a torque value, for example, using a mathematical expression or a look-up table. The angular distance value may be indicative of an angular distance between the first ring 111 and the second ring 112.

The method comprising steps a) to e) is a method of measuring angular distances and/or a method of measuring torque values in a manner that is highly immune to magnetic interference fields.

Although it has been described so far that the magnetic structure 110 is mainly used for a torque sensor, this is not the only application, and the magnetic structure 110 may also be used as an angle sensor, in particular for measuring an angle between the first ring 111 and the second ring 112. The present invention therefore also provides an angle sensor capable of measuring the angle between the two

rotatable rings

111, 112 in a manner that is highly robust to external disturbing fields.

In summary, the magnetic

field sensor arrangements

220, 320 and the angle sensor and magnetic

torque sensor arrangements

200, 300 disclosed herein are very beneficial for determining the signal magnetic flux generated by the signal magnetic field source S1 without being significantly adversely affected by external stray/interfering magnetic fields. This is due to the specific structure and the specific arrangement of the first and the second flux concentrator, and the arrangement of the magnetic field sensor between the two flux concentrators, as disclosed herein, in particular in the air gap formed by the radial orientation of the gap direction 206.

Although an interfering magnetic field oriented in any direction may superimpose signal magnetic flux within the two flux concentrators, the present invention provides means to correct the measurement results containing both signal magnetic flux and interfering magnetic flux sensed in the first sensing direction (in the gap direction 206) by: the interfering magnetic flux 229 outside the two flux concentrators in the second sensing direction (perpendicular to the gap direction) is determined and the amount of interfering magnetic flux sensed in the second sensing direction is scaled and subtracted from the measured magnetic flux in the first sensing direction (gap direction) to substantially acquire the signal magnetic flux generated by the signal magnetic source S1 and optionally modulated by the magnetic structure 110.

Claims

1. A magnetic field sensor arrangement (220; 240; 250; 320) for determining a signal magnetic flux generated by a signal magnetic field source (S1) in a manner substantially immune to magnetic interference fields, the magnetic field sensor arrangement comprising:

the signal magnetic field source (S1);

a first magnetic flux concentrator (201; 221; 251; 301) and a second magnetic flux concentrator (202; 222; 252; 302) configured and arranged such that an air gap (203) is formed between an outer face (204) of the first magnetic flux concentrator and an outer face (205) of the second magnetic flux concentrator, wherein the first outer face (204) and the second outer face (205) define a first direction (X) of the air gap (203) by a line of shortest distance between the outer faces (204, 205);

wherein the first and second flux concentrators are configured for directing a signal magnetic flux generated by the signal magnetic field source (S1) substantially in a first direction (X) to and through the air gap (203);

a magnetic field sensor (207) comprising a plurality of sensor elements arranged inside the air gap (203);

wherein the magnetic field sensor is configured for measuring a first signal (Bx) indicative of a magnetic field component oriented in the first direction (X), and for measuring a second signal (Bz) indicative of a magnetic field component oriented in a second direction (Z) substantially perpendicular to the first direction (X);

and wherein the magnetic field sensor (207) is further configured for reducing or substantially eliminating the influence of a magnetic interference field, if present, based on the first signal (Bx) and the second signal (Bz).

2. The magnetic field sensor arrangement (220; 240; 250; 320) of claim 1,

characterized in that the magnetic field sensor (207) is configured to reduce or substantially eliminate the influence of the magnetic interference field, if present, by scaling the second signal (Bz) with a predefined constant and by subtracting the scaled signal from the first signal (Bz).

3. The magnetic field sensor arrangement (220; 240; 250; 320) of claim 1,

characterized in that the magnetic field sensor (207) further comprises a processor unit and a memory unit.

4. An angle sensor arrangement comprising:

the magnetic field sensor arrangement (220; 240; 250; 320) of claim 1;

a first ring (111) comprising a plurality of claws (113), the first ring being arranged adjacent to the first magnetic flux concentrator;

a second ring (112) comprising a plurality of claws (114), the second ring being arranged adjacent to the second magnetic flux concentrator;

the first and second rings are movable about an axis of rotation (115) and relative to each other;

and wherein the magnetic field sensor (207) is further configured for converting the signal magnetic flux into an angular distance signal indicative of an angular distance between the first ring and the second ring.

5. Angle sensor arrangement according to claim 4,

characterized in that the magnetic field sensor (207) is configured for measuring a first magnetic field component (Bx) in a radial direction (X) with respect to the rotation axis (115); and is

Wherein the magnetic field sensor (207) is configured for measuring a second magnetic field component (Bz) in an axial direction (Z) parallel to the rotational axis (115).

6. Angle sensor arrangement according to claim 4,

characterized in that the outer face (204) of the first magnetic flux concentrator (201, 301) is arranged on a portion (222, 223, 303) of the first magnetic flux concentrator (201, 301), which portion (222, 223, 303) has a protruding or curved portion or an L-shaped cross-section in a plane containing the rotational axis (115) and the first direction (X);

and/or wherein the outer face (205) of the second magnetic flux concentrator (202, 302) is arranged on a portion of the second magnetic flux concentrator (202, 302) having an L-shaped cross-section in a plane containing the rotational axis (115) and the first direction (X).

7. An angle sensor arrangement according to claim 6,

characterized in that the L-shaped portion (222, 223) of the first and/or the second magnetic flux concentrator (201, 301; 202, 302) comprises a long leg (224) and a short leg (225, 226), wherein the long leg (224) is longer than the short leg (225, 226) and is oriented substantially perpendicular to a gap direction (206);

and/or wherein the outer face (204) of the first magnetic flux concentrator (201, 301) is arranged on a portion (222, 223, 303) of the first magnetic flux concentrator (201, 301) forming a free end of the first magnetic flux concentrator (201, 301);

and/or wherein the outer face (205) of the second magnetic flux concentrator (202, 302) is arranged on a portion (305) of the second magnetic flux concentrator (202, 302) forming a free end of the second magnetic flux concentrator (202, 302).

8. An angle sensor arrangement according to claim 6,

characterized in that the outer face (204) of the first magnetic flux concentrator (301) is arranged on a portion (303) of the first magnetic flux concentrator (201, 301) comprising at least one fin-shaped extension member (304) and/or the outer face (205) of the second magnetic flux concentrator (302) is arranged on a portion (305) of the second magnetic flux concentrator (302) comprising at least one fin-shaped extension member (306, 307, 308), wherein the at least one fin-shaped extension member (304, 306, 307, 308) extends in a direction oriented substantially perpendicular to the first direction (X) beyond a width (209) and/or a height (210) of a cross section of the air gap (203), wherein the cross section of the air gap (203) extends substantially perpendicular to the first direction (X).

9. Angle sensor arrangement according to claim 4,

characterized in that the magnetic field sensor (207a) comprises a semiconductor substrate located substantially inside the air gap (203) and oriented such that the axial direction (Z) is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate comprises an integrated magnetic concentrator IMC and at least two horizontal Hall elements arranged at the periphery of the IMC;

or wherein the magnetic field sensor (207b) comprises a semiconductor substrate located substantially inside the air gap (203) and oriented such that the first direction (X) is perpendicular to the semiconductor substrate, and wherein the semiconductor substrate comprises an integrated magnetic concentrator IMC and at least two horizontal Hall elements arranged at the periphery of the IMC;

or wherein the magnetic field sensor (213a) comprises a semiconductor substrate located substantially inside the air gap (203) and oriented such that the semiconductor substrate is perpendicular to the axial direction (Z), and wherein the semiconductor substrate comprises a horizontal Hall element (214b) and a vertical Hall element (214 a);

or wherein the magnetic field sensor (213b) comprises a semiconductor substrate located substantially inside the air gap (203) and oriented such that it is parallel to the axial direction (Z) and to the first direction (X), and wherein the semiconductor substrate comprises a first vertical Hall element (216a) sensitive in the first direction (X) and a second vertical Hall element (216b) sensitive in the axial direction (Z);

or wherein the magnetic field sensor (207c) comprises a semiconductor substrate located substantially inside the air gap (203) and oriented such that the semiconductor substrate is perpendicular to the radial direction (X), and wherein the semiconductor substrate comprises a horizontal Hall element (212c) and a vertical Hall element (212 d).

10. A magnetic torque sensor arrangement for stray field immune determination of torque exerted on a torque rod, comprising:

an angle sensor arrangement according to claim 4;

the torque rod having a first axial end connected to the first ring (111) and a second axial end connected to the second ring (112) such that when a torque is applied to the torque rod, the torque rod is elastically deformed, resulting in an angular displacement of the first and second rings as a function of the applied torque;

and wherein the magnetic field sensor (207) is further configured for converting the signal magnetic flux or the angular displacement into a torque value.

11. A method of determining a signal flux generated by a signal magnetic field source (S1) in a manner substantially immune to a magnetic interference field, comprising the steps of:

a) providing (1201) a magnetic field sensor arrangement according to claim 1;

b) measuring (1202) a first signal (Bx) of a magnetic field component oriented in the first direction (X) by the magnetic field sensor (207);

c) measuring (1203), by the magnetic field sensor (207), a second signal (Bz) of a magnetic field component oriented in the second direction (Z) perpendicular to the first direction (X);

d) reducing or substantially eliminating (1204) the effect of the magnetic interference field, if present, based on the first magnetic field component (Bx) and the second magnetic field component (Bz).

12. The method of claim 11, wherein step d) comprises: scaling the second signal (Bz) with a predefined constant and subtracting the scaled signal from the first signal (Bx).

13. The method according to claim 11, characterized in that step d) is performed by a processor unit and a memory unit integrated in the magnetic field sensor (207).

14. The method of claim 11, wherein the first and second light sources are selected from the group consisting of,

wherein step a) further comprises: providing a first ring (111) comprising a plurality of claws (113), the first ring being arranged adjacent to the first magnetic flux concentrator; and providing a second ring (112) comprising a plurality of claws (114), the second ring being arranged adjacent to the second magnetic flux concentrator; the first and second rings are movable about an axis of rotation (115) and relative to each other;

and wherein the method further comprises the steps of:

e) the corrected first signal is converted (1205) into an angle value.

15. The method of claim 11, wherein the first and second light sources are selected from the group consisting of,

wherein step a) further comprises: providing a torque rod having a first axial end connected to the first ring (111) and a second axial end connected to the second ring (112), such that when a torque is applied to the torque rod, the torque rod elastically deforms, resulting in an angular displacement of the first and second rings as a function of the applied torque;

and wherein the method further comprises the steps of:

e) the corrected first signal is converted (1205) into a torque value.